Apr., 1916
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TABLEI Naphtha-Soluble Bitumen MATERIAL Penetration (Pure Basis) 200 64.3 Texas residual.. California residual. . , . , , , , , 220 65.0 72.2 Mexican residual.. . . . . . . . . . . 220 73.1 Trinidad residual. . . . . . . . . . . 23 71.9 Bermudez refined a s p h a l t . . . . 17' 40 64.. 9 Trinidad refined asphalt. ....
............
.
PER CENT UNSATURATED HYDROCARBONS -Amount Removed by-SATURATED HYDROCARBONS HzSOa (HC0H)a Total over By Ordinary By Fuming By Fuming over over Fuming Ordinary HzSOi HzSOl (HC0H)a Ordinary HzSOa &SO4 H604 44.5 40.1 37.5 32.7 28.3 23.7
+
again, t h e native asphalts from these. I t appears t h a t t h e more thoroughly asphaltic a bitumen is t h e smaller t h e a m o u n t of saturated hydrocarbons it contains, as evidenced b y t h e residue left b y the treatment of t h e total bitumen, not only with sulfuric acid a n d paraformaldehyde b u t likewise with fuming a n d even with concentrated sulfuric acid. I n view of these facts i t hardly seems necessary t o extend, for t h e purpose of differentiating bitumen of this type, t h e t r e a t m e n t t o t h e use of formaldehyde since t h e y are, essentially, as well differentiated b y t h e use of ordinary a n d fuming sulfuric acid. The differentiation b y means of t h e formolite reaction is, however, of great value as confirming our previously conceived ideas t h a t t h e more satisfactory form of b i t u m e n , from its consideration as a cementing material, is t h e one containing t h e smaller proportions of saturated hydrocarbons. T h e native or natural asphalts from t h e Trinidad a n d Bermudez deposits consist largely of unsaturated hydrocarbons, followed b y t h e Trinidad residual pitch, whereas t h e residuals prepared from Mexican, California, a n d Texas oils contain very much higher percentages 'of saturated hydrocarbons, from which fact, in t h e light of practical experience, t h e deficiencies of the artificial asphalts in their industrial behavior, as demonstrated b y service tests, may be considered t o be satisfactorily explained. T h e results here presented, as far as t h e y relate t o t h e a m o u n t of saturated compounds unacted upon b y ordinary sulfuric acid for t h e various materials, m a y be compared with an earlier s t u d y of t h e same subject b y t h e writer, t h e results of which were published in the Engineering Record of April 2 6 , 1913. The comparison is shown b y t h e following figures: P E R CENT O F MATERIALSUNACTED UPON B Y ORDINARY HzSOa
Tex. Year Oil 1913 . . . . . . . . . 48.1 1914 . . . . . . . . . 4 4 . 5
Cal. Oil 30.0 40.1
Mex. Trinidad Bermudez Oil 33.4 37.5
Asphalt 24.6 32.7
+
PERCENT
Asphalt 24.0 28.3
Trinidad Refined Asphalt 24.4 23.7
From t h e earlier results t h e same conclusions can be and were drawn as t o t h e nature of these materials as from t h e present data. T h e two show considerable differences, except in t h e case of t h e Trinidad refined asphalt. This may be accounted for b y t h e fact t h a t all oil products are extremely variable in character, owing t o t h e variations in t h e charact.er of the petroleum from which t h e y are prepared a n d of the lack of regularity in t h e processes b y which t h e preparation is carried out. The Trinidad asphalt alone, being a substance of a very uniform character, would be expected, as it does, t o give uniform results, when examined a t intervals. I n conclusion, t h e writer desires t o t h a n k Dr. Philip
Schneeberger, who has efficiently carried out t h e laboratory work which has supplied t h e d a t a for this paper. WOOLWORTH BUILDINO,NEW YORK
THE DETERMINATION OF CARBON IN STEELS AND IRONS BY DIRECT COMBUSTION IN OXYGEN AT HIGH TEMPERATURES' By J. R. CAIN A N D H.
E. CLEAVES
Received January 6, 1916
T h e influence of temperature on t h e results obtained b y t h e direct combustion of steel a n d iron in oxygen has been frequently investigated2 and t h e general consensus of opinion seems t o be t h a t higher results for carbon are obtained with higher combustion temperatures. This conclusion, however, is rendered doubtful b y a number of circumstances: (I) Quite frequently, because of uncertainties in blanks, it is impossible t o conclude whether the difference in results claimed is due t o variation in blank or is real. ( 2 ) The published work does not indicate t h a t investigators have always assured themselves t h a t t h e material used t o support the drillings or t h a t t h e fluxes sometimes used are completely free from carbon. (3) Differences in carbon results with t h e same steel are frequently due t o a variation in t h e size of drillings used. Combustions of steel are ordinarily made in such a way t h a t t h e oxides are in the fused condition for only a very short time: this is evident from work done here, which shows t h a t t h e fusion point of t h e oxides themselves is above 1450' C.,3 a n d t h a t as soon as t h e fused material has combined with or permeated the bed material the melting point of t h e combination becomes much higher. The temperature of a combustion furnace as ordinarily operated does not exceed I Z O O O a n d usually lies between 950' a n d 1100";hence it is evident t h a t the oxides from I or z g. of steel must solidify very rapidly after the combustion period is over, for it is only during this time t h a t t h e temperature is above the melting point of t h e oxides. Burning in t h e ordinary way, if the sample consists of very large particles, there is always t h e danger of incomplete combustion of all its parts; on t h e other hand, if the particles are very small t h e combustion may proceed so rapidly as t o cause initial fusion of a portion of t h e oxides followed b y quick solidifica1 This paper is an amplification of a preliminary paper on this subject b y t h e same authors. See J . Wash. Acad. Sci., 4 (1914), 893. 2 See Lorenz, 2 . angezn. Chem., 6, 313, 395, 411, 635; and Foerster, Z . anoyg. Chem., 8 (1895), 274, for work a t high temperatures; for references t o work a t other temperatures, see article b y Mueller and Diethelm, 2 . angew. Chem.. 27 (1910). 2114. By G. K. Burgess and R. G . Waltenburg, unpublished
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tion of t h e fused part with resultant enclosure of yet monoxide showed none of this gas t o be present. I t unburned metal. There is some chance, too, t h a t seems fair t o conclude from this experiment t h a t a n y carbon dioxide or monoxide may be enclosed in t h e error i n ordinary combustions resulting from occlusion solidified mass. and t h a t with certain alloy steels, diffi- or inclusion of carbon dioxide or monoxide is q u i t e cultly oxidizable carbides (silicon, tungsten, chromium) negligible. The case might be different where silica is m a y escape oxidation except a t very high temperatures. used as supporting material for drillings and there is A consideration of these facts, together with previous consequently t h e possibility of forming viscous: slowly experimental work here and elsewhere, which showed solidifying slags which might well retain large bubbles t h a t oxides from apparently well-burned samples of gas. I t should be noted in this connection t h a t yielded additional carbon upon being finely pulverized immediately after t h e combustion of metal has ceased a n d reburned, led t o t h e development of t h e present the partial pressure of carbon dioxide and monoxide method. in which t h e sources of error cited in t h e first inside t h e combustion t u b e reaches a maximum paragraph are eliminated. The object of this work because t h e incoming oxygen has been almost comwas t o develop a procedure which would giT-e t h e pletely consumed b y the metal. leaving ,but little best possible chance for oxidation and liberation of excess t o sweep on t h e products of combustion; t h e all t h e carbon in t h e sample, regardless of t h e original oxides begin t o freeze very soon after, a n d , accordingly. size of driliings. and especially t o ascertain b y such conditions are t h e n Irery favorable for retention of method t h e order of t h e error. if a n y , vhich affected carbon dioxide or monoxide b y t h e solidifying oxides. t h e carbon determinations reported on t h e certificates Hou-ever, as stated. when non-viscous. quickly solidifor t h e Bureau's series of s t a n d a r d analyzed irons and fying oxides result, as in our experiment, t h e error from steels. The latter determinations were made as this cause may be regarded as negligible. For carrying out combustions under t h e conditions usual, either b y direct combustion of t h e metal a t temperatures of 950' t o IZOO', or else b y burning selected b y us-initial temperatures of 10joO t o IIOO' the carbon residue left after solution of t h e steel or followed by temperatures above 14 j o c and burning was iron in a suitable solvent.' Briefly. our method t h e metal directly supported on platinum--it consisted in burning t h e metal directly in oxygen necessary either t o s t a r t with lorn temperatures and within t h e usual temperature range, t h e n raising t h e temperature t o a point above t h e fusion point of t h e oxides ancl maintaining this temperature long enough t o insure t h a t all parts of t h e sample had been brought in contact with oxygen or fused iron oxide. The sample was burned directly on platinum (with precautions described later) so t h a t no carbon could FIG.I-DET.4ILS OF A P P A R A T U S he obtained from t h e support for t h e drillings; t h e CI and C2, porcelain tubes filled with copper oxide and wound with nichrome wire for heating; T. tower filled with stick K O H ; F, g a s lurnace: carbon was estimated b y t h e barium carbonate tiA, tube for air-cooling; RI, Meyer bulb; S, soda-lime guard-tube tration method de\-ked b y one of t h e authors? and i n slow oxygen current, increasing both as t h e skin of such way t h a t t h e blank was negligible. oxide on t h e grains became thick enough t o protect I t seemed first desirable t o know m-hether carbon t h e platinum, or else t o burn initially in a furnace dioxide or monoxidc n-ere left enclosed in t h e oxides kept at t h e lower temperatures and t h e n transfer t h e produced during t h e direct combustion process as boat and contents t o t h e high-temperature furnace. ordinarily carried o u t . T o determine this there was The first method 17-as carried out in t h e gas furnace used a n apparatus consisting of an evolution flask shown in Figs. I and 11;' t h e second procedure w a s connected t o a suitable purifying train followed b>- used v-ith our usual nichrome-wound furnaces in absorption tubes for carbon dioxide and m o ~ i o x i d e . ~conjunction ivit h t h e plat in u m - w o un d furnace shown in i n t h e evolution flask therc was placed a large excess Fig. 111. I n x-ien- of t h e failure t o find notably higher of concentrated hydrochloric acid together with t h e results b y our method ( a s ill appear later) we did x.ncrushct1 oxides resulting from t h e combustion in not deem it worth while t o proceed t o the next obvious tlic ordinary way (on pure alun-dum) of tn-enty-tx7-o step in apparatus--- t h e construction of a single electric 2-g. samplcs of steels known t o yield carbon upon furnace suitable for hot,h stages of t h e combustion. rcburning after pulverizing. Boiling th.e contents of The electric furnace method is very much t o be pret h e flask for seT-eral hours resulted in complete solu- ferred. The required temperatures are reached and t i o n of ex-erything except t h e mechanically held maintained n.ith much greater regularity and conalunduin, and d u r i n g r his tinic a current of air puri- venience t h a n when gas is used, t h e wear on t h e platified from carbon dioxidc and monoxide was passed n u m is less and t h e chance for error from extraneous through t h e apparatus. The carbon dioxide found carbon dioxide is eliminated. T h e gas furnace is very in t h e nbsorption t u b e \\-aso.00104 g., which n-odd cor- destructive in its eflects on t h e combustion t u b e ; respond to 0.000; per cent carbon on t h e basis of 44 t h e boats seem t o suffer very little b y either method. grams of metal zaken; t h e absorption t u b e for carbon If, however, t h e operation of t h e gas furnace is con1 In a Ten c a i e i certihcate re5ult- include the carbon obtained from reducted carelessly so t h a t t h e temperature initially b x i i i n g t h e oxide? is caused t o rise too rapidly a n d t h e fusion tempera2 J. 1:. Cain. B u r 01 S l a n d a r d ~ . P u $ u 3 3 ; THISJOT-RSAL, 6 (1914), 465. 3
Both palladium chloride and iodine pentoxide tubes irere used.
1 Reproduced irom our first paper on high temperature carhon corn bustions, above cited
Apr., 1916'
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was effected; then the temperature mas raised t o I O ~ O ' or 1100' and the combustion of the iron completed. As soon as absorption of oxygen b y t h e burning metal had ceased t h e blow-pipe flame was turned on full, this stage of t h e combustion being continued 2 j t o 30 min. The Meyer tube was disconnected and t h e determination finished b y filtering off and washing the precipitated barium carbonate and titrat-
ture of t h e oxides is reached before all the iron is burned, then a boat is soon destroyed b y alloying with iron; this is also t h e case if the combustion of metal is incomplete in t h e first electric furnace when using t h a t method. Temperatures were measured with a Wanner optical pyrometer a n d with a platinumiridium thermoelement in conjunction with a millivoltmeter. The low temperature electric furnace
demrn PimlnvmW
